[LiveComponent] Cache the attribute-method lookups per component class

[Kocal]

Q	A
Bug fix?	no
New feature?	no
Deprecations?	no
Documentation?	no
Issues	-
License	MIT

liveListeners(), preDehydrateMethods(), postHydrateMethods(), preReRenderMethods() and isActionAllowed() each rebuild a ReflectionClass and walk every public method of the component, on every render and every request, even though what they return only depends on the component class.

Memoize the resolved methods per class and attribute. An earlier revision of this branch put the cache in AsTwigComponent, where those helpers live, but they have no other consumer than AsLiveComponent, so the cache belongs here and TwigComponent is left untouched.

Timings use the call counts from the review: a page holding five LiveComponents calls liveListeners() and preDehydrateMethods() once per component on the initial render, and a single component update calls each of the five once.

initial render, 5 components   18.1 us -> 2.9 us
one component update            8.2 us -> 1.0 us

Sixteen microseconds off a page render isn't going to show up in a profile; the ratio is what it is because reflection simply isn't needed more than once per class.

Benchmarked from the repository root with symfony php bench.php:

<?php
require __DIR__.'/src/LiveComponent/vendor/autoload.php';

use Symfony\UX\LiveComponent\Attribute\AsLiveComponent;
use Symfony\UX\LiveComponent\Attribute\LiveAction;
use Symfony\UX\LiveComponent\Attribute\LiveListener;
use Symfony\UX\LiveComponent\Attribute\PostHydrate;
use Symfony\UX\LiveComponent\Attribute\PreDehydrate;
use Symfony\UX\LiveComponent\Attribute\PreReRender;

#[AsLiveComponent('Bench')]
class BenchComponent
{
    #[PreDehydrate] public function onPreDehydrate() {}
    #[PostHydrate] public function onPostHydrate() {}
    #[PreReRender] public function onPreReRender() {}
    #[LiveAction] public function save() {}
    #[LiveListener('foo:bar')] public function onFooBar() {}

    public function noise1() {} public function noise2() {} public function noise3() {}
    public function noise4() {} public function noise5() {} public function noise6() {}
}

$component = new BenchComponent();

$render = static function () use ($component) {
    for ($i = 0; $i < 5; ++$i) {
        AsLiveComponent::liveListeners($component);
        AsLiveComponent::preDehydrateMethods($component);
    }
};
$update = static function () use ($component) {
    AsLiveComponent::liveListeners($component);
    AsLiveComponent::preDehydrateMethods($component);
    AsLiveComponent::postHydrateMethods($component);
    AsLiveComponent::preReRenderMethods($component);
    AsLiveComponent::isActionAllowed($component, 'save');
};

foreach (['initial render' => $render, 'one update' => $update] as $label => $fn) {
    $fn();
    $start = hrtime(true);
    for ($i = 0; $i < 2000; ++$i) { $fn(); }
    printf("%-16s %6.1f us\n", $label, (hrtime(true) - $start) / 1e3 / 2000);
}

Blackfire:

• before: https://app.blackfire.io/envs/5f4f9a62-eaa0-45ee-b7b3-a1b879f550e9/profiles/8f8d948b-732a-44ca-a0a3-ebb9cbc48637/graph
• after: https://app.blackfire.io/envs/5f4f9a62-eaa0-45ee-b7b3-a1b879f550e9/profiles/f0d0d013-2120-471b-8569-f0866a905d9e/graph
• diff: https://app.blackfire.io/envs/5f4f9a62-eaa0-45ee-b7b3-a1b879f550e9/profiles/compare/8f8d948b-732a-44ca-a0a3-ebb9cbc48637...f0d0d013-2120-471b-8569-f0866a905d9e/graph

Analysis, implementation and benchmarks by Claude Opus 5.

[smnandre]

// Mimics 20 requests for a page holding 20 live components.
for ($i = 0; $i < 20 * 20; ++$i) {

Not a very realistic mimic :)

Assuming 20 independent LiveComponents rendered once on the initial page:

Helper	Initial render	One component update
liveListeners()	20	1
preDehydrateMethods()	20	1
postHydrateMethods()	0	1
preReRenderMethods()	0	1
isActionAllowed()	0	1 for a custom LiveAction, otherwise 0

And I'm not sure to get the "n requests in parralel" is doing here.

But if there are some gain for 2/5 of them, why not 👍

Now, i'm not very happy we re-contaminate TwigComponent with code made for LiveComponent, and i'd rather we have these methods in the AsLiveComponent attribute directly if possible..

[Kocal]

Benchmarks updated with a more real-world usage, now only LiveComponent is modified